Kenya's deputy president has denounced the killing of 28 bus passengers by Islamic extremists and said the nation's military responded by killing more than 100 militants in Somalia.

William Ruto, speaking on national broadcasting Sunday, said Kenya is a target of international terrorist groups, including Somalia's al-Shabab, which is linked to al-Qaida. He said Kenya's security forces will protect citizens including by raiding mosques.

Al-Shabab said the bus attack, in which 28 non-Muslims were singled out and killed Saturday, was in retaliation for the closure of four mosques by Kenyan authorities last week.

Ruto defended the raids on the mosques, saying the houses of worship had been converted into armories and centers for plotting terrorism.

Kenyan authorities said they found explosives and a pistol when they searched the mosques.